Pad for covering contoured cushion spring structure



May 25, 1965 J. s. MEYERS PAD FOR COVERING CONTOURED CUSHION SPRING STRUCTURE Filed Dec. 7, 1962 JOHNYEQS @MJ W] ATTORNEY 1 United States Patent PAD FOR COVERING CONTOURED CUSHION SPRING STRUCTURE John S. Meyers, Allen Park, Mich, assignor, by mesne assignments, to Hoover Ball and Bearing Company, Saline, Mich, a corporation of Michigan Filed Dec. 7, 1962, Ser. No. 242,951 1 Claim. (Cl. -345) The present invention relates to improvements in pad construction used upon seats and particularly seats of vehicles.

In the design and fabrication of spring structure for vehicle seats, it has long been the practice to so design and arrange the spring elements that the resilient loadsupporting surface, upon which the seat pad is imposed, is of convex form. The convex form or crown of the load-supporting surface extends from front to rear of the seat and the crown may be as much as an inch or more in height.

In the past, it has been the practice to use a flat pad upon the crowned pad-supporting surface of the spring structure. It has been found that the flat unshaped pad will assume the convex shape of the spring structure when the exterior cover of the trim is applied to the top of the pad and pulled down to its finished position.

To protect the pad of foam rubber, urethane foam, or the like, from the abrasive action of the spring elements constituting the resilient supporting structure of the spring structure of the seat, and to effect better distribution of the load supported upon the pad and spring elements, it has been proposed to attach a so-called insulator pad to the underside of the top pad of rubber, urethane, or other resilient material. However, it has been found that when the insulator pad is attached to the underside of a flat unshaped top pad and the assembly of the two pads is used to upholster the crowned spring assembly, that the insulator pad, bonded on the underside of the top pad, has a tendency to buckle lengthwise of the seat cushion during the trimming operation. This results in a hard, uncomfortable ridge extending throughout the length of the cushion.

A further difiiculty arising from the bonding of the insulator pad to the underside of the top pad is that the differential in shrinkage of the upper and lower surfaces of the pad, which takes place during curing, is greater in respect to the upper surface, causing the same to become concave.

According to the present invention, the above mentioned difficulties may be overcome through the use of a contour molded top pad to which the insulator pad is bonded upon the contoured underside. When such an assembly is applied to the spring structure and trimmed in the usual manner, a completely smooth and satisfactory seat cushion results and the effects of the differential shrinkage are minimized.

Thus, an object of the invention is to provide an improved top pad and insulator pad assembly for crowned seat structures of the type described.

Another object is to provide an improved pad and insulator assembly in which at least the undersurface of the pad to which the insulator structure is attached has a molded contour which substantially corresponds to the crown of the load-supporting surface of the spring structure.

Another object is to provide a urethane pad for seat structures which is of molded contour and has a concave undersurface to which an insulator pad has been bonded and which conforms to the contour thereof.

These and other objects and advantages of the present invention will more fully appear from the following specification and the appended claims.

In the drawings,

FIG. 1 is a plan view of a full width top pad for a vehicle seat as viewed from the underside,

FIG. 2 is a cross-sectional view taken on line II-II of FIG. 1 transversely of the longitudinal axis of the top P FIG. 3 is an end view of FIG. 1 on a slightly larger scale,

FIGS. 4 and 5 are fragmentary sectional views taken on lines IVIV and VV, respectively, of FIG. 3.

The top pad 10 is preferably of molded resilient urethane foam of suitable formulation. In practice, the mold will be in two parts with the underside of the cover completing the contour of the pad as the foaming action is being carried out in the lower part of the mold, in a manner disclosed in US. Patent No. 3,056,168. The contour of the lower part of the mold, in the illustrated form of the invention, is such that the sides and front of the pad 10 has a skirt portion 12 while the contour of the underside of the cover of the mold provides the thickened edge, as shown in FIGS. 4 and 5.

In carrying out the principles of the present invention, it will be noted in FIG. 2 that throughout the width of the top pad 10, the front to rear contour is slightly crowned by the contour of the mold parts to substantially conform to the crown of the spring structure upon which the top pad 10 is superimposed. The upper surface 14 is shown concave and the undersurface 16 is convex with the surfaces 14 and 16 being complementary.

Bonded or otherwise attached to the undersurface 16 is an insulator pad 18 which may consist of salvage twisted paper cords 20 at opposite ends of a sheet of burlap 22 carrying small, closely spaced wires 21 which are interwoven with the burlap and have their ends wrapped around the cords 20. In practice, the insulator pad 18 will be placed upon the convex underside of the mold cover. As the foaming takes place the foam penetrates the interstices of the burlap to embed the warps and wefts in the foam to firmly bond the insulator pad to the undersurface of the top pad 10. This bonding of the insulator to the top pad is more fully disclosed in US. Patent No. 2,985,230.

It should be understood that it is the contour of the undersurface 16 of the top pad 10 which must substantially correspond to the crown of the spring structure upon which the top pad 10 and insulator pad assembly is placed if the problem experienced with fiat top pads, discussed above, is to be obviated. Thus, the contour of the uppersurface 14 need not be complementary to the surface 16 although this will usually be the case in practice.

For the reason that the presence of the insulator pad 18 causes differential shrinkage of the upper and lower surfaces of the pad 19 upon curing of the foam, this differential will result in the contour of the top surface of the pad 10 being of a lesser crown than the undersurface when the crown of the upper and lower die parts are the same. For this reason, it may be desirable to have the concavity of the lower die part greater than the crown'of the underside of the mold cover so that the finished pad 10, as a A top pad and insulator pad assembly for vehicle seats 7 and the like, comprising a molded top padof resilient reaction material such as foam rubber, foam urethane, and the like, the undersurface of said top pad having a molded front-to-back concave contour substantially complementary to the crown of the spring structure of the seat, and a flexible insulator pad bonded to said undersurface and conforming to the contour of said undersurface, said insulator pad having spaced wires disposed normal to 4- the direction of concavity ot the contour of said undersurface.

References Cited by the Examiner UNITED STATES PATENTS 2,283,116 5/42 Young 5354 X 2,779,036 1/57 Platt 5-354 2,785,440 3/57 Toulrnan 26425 2,985,230 5/61 tern 267-94 X 3,870,814 1/63 Withoff 5354 FRANK 'B. SHERRY, PrimaryExamincr. 

